1. Field of the Invention
The invention relates to an electronic register device for recording movements of the lower jaw of a person relative to the upper jaw of the person, which register device has a bite fork for recording a position of the upper jaw relative to reference points on the head of the person, wherein the bite fork is designed to receive a plastic compound for recording an impression of the dentition of the upper jaw, and a lower-jaw attachment for recording movements of the lower jaw relative to the upper jaw.
2. Related Technology
To produce tooth replacements such as crowns and bridges, it is known to form models of the dentition of an upper jaw and of the associated lower jaw from wax and to optimize the shape of these models in an articulator, through articulation movements, until a harmonious movement of the tooth shapes in relation to one another is obtained. This is referred to as a functional comparison. In this way, it is subsequently possible to avoid time-consuming grinding work in the mouth of the patient concerned.
According to the prior art, the tooth shape optimized in the articulator is then recorded by scanning and, in a further step, the desired tooth replacement, for example the crown or bridge, is produced, preferably from ceramic, using a CAD CAM milling/grinding machine and the data recorded by the scanning procedure.
A kind of “virtual articulator” is also known. This involves software with which a movement of the two scanned plaster models of the upper jaw and lower jaw relative to each other can be simulated. To be able to determine adjustment data for this virtual articulator, it is first necessary to produce the corresponding plaster models of the dentition of the upper jaw and lower jaw; the adjustment values then have to be determined using these plaster models and a mechanical articulator. This requires quite a lot of work.
WO 2007/020091 A1 discloses an electronic register device which is sold by the applicant under the trade name “ARCUS digma” and which is used to adjust articulators. An electronic analysis of the position of the lower jaw can be performed with this device. In order to measure the movements of the lower jaw relative to the upper jaw, a carrier frame is connected in each case to the upper jaw and the lower jaw. The carrier frame connected on the upper part of the head to the upper jaw, and hereinafter also called the “head part,” is provided with four microphones in the form of ultrasound receivers, while the carrier frame connected to the lower jaw, and hereinafter also called the “lower-jaw attachment”, is provided with three corresponding ultrasound transmitters. The twelve paths between the three transmitters and the four microphones are evaluated in respect of their changes in length during movements of the lower jaw relative to the upper jaw. FIGS. 2A, 2B, 2C, and 2D show sketches of the lower-jaw attachment from different perspectives.
The head part includes a base element with support elements for supporting the head part on the head of the person concerned or of a patient. These support elements can in particular comprise two rearward bearing elements, which are designed to rest in the area of the two ears, and a nose support, which is designed to rest on the upper nose.
Moreover, the known electronic register device ARCUS digma includes a bite fork, which serves to record the position of the dentition of the upper jaw relative to the auditory canals. FIGS. 1A, 1B, 1C, and 1D show sketches of the bite fork from different perspectives.